1. Technical Field
The present invention relates to a method of determining a number of patches.
2. Related Art
Color printers capable of printing a plurality of colors have come into widespread use. In a color printer, color calibration is performed in order to improve color reproducibility. When color calibration is performed, a test chart for color calibration is printed. The color of the test chart is measured to acquire a colorimetric value in a color space, and the misalignment of the colors printed by the printer is corrected on the basis of the colorimetric results (for example, see JP-A-2006-237987).
However, even when colors with the same gradation level are printed over the entire surface of a sheet, a little color unevenness occurs in the sheet. This is because there is a small variation in the transport amount of a sheet or the discharge amount of ink droplets when an ink jet printer performs printing.
The degree of color unevenness occurring in the sheet varies depending on the ink color used. For example, in order to improve calibration accuracy, the number of patches of a color having a large degree of color unevenness is increased, and the number of patches of a color having a small degree of color unevenness is decreased. When the number of patches is insufficient, the accuracy of correction by calibration is lowered. When the number of patches is large, the time required for colorimetry is increased. Therefore, it is preferable to appropriately adjust the number of patches of each ink color used.